Documentation

This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

grayslice

Convert grayscale image to indexed image using multilevel thresholding

Syntax

X = grayslice(I, n)

Description

X = grayslice(I, n) thresholds the intensity image I returning an indexed image in X. grayslice uses the threshold values:

X = grayslice(I, v) thresholds the intensity image I using the values of v, where v is a vector of values between 0 and 1, returning an indexed image in X.

You can view the thresholded image using imshow(X,map) with a colormap of appropriate length.

Class Support

The input image I can be of class uint8, uint16, int16, single, or double, and must be nonsparse. Note that the threshold values are always between 0 and 1, even if I is of class uint8 or uint16. In this case, each threshold value is multiplied by 255 or 65535 to determine the actual threshold to use.

The class of the output image X depends on the number of threshold values, as specified by n or length(v). If the number of threshold values is less than 256, then X is of class uint8, and the values in X range from 0 to n or length(v). If the number of threshold values is 256 or greater, X is of class double, and the values in X range from 1 to n+1 or length(v)+1.

Examples

collapse all

Read grayscale image into the workspace.

I = imread('snowflakes.png');

Threshold the intensity image, returning an indexed image.

X = grayslice(I,16);

Display the original image and the indexed image, using one of the standard colormaps.

imshow(I)

figure
imshow(X,jet(16))

See Also

Introduced before R2006a

Was this topic helpful?